Hydroforming process



Patented June 29, 1954 HYDROFORMIN G PROCE SS Isidor Kirshenbaum, Union, N. .L, assigno'r to Standard Oil Development Company, a corporation of Delaware N '0 Drawing. Application December 1, 1950,

Serial No. 198,717

6 Claims.

This invention pertains to improvements in the catalytic conversion of hydrocarbons and more particularly to the conversion of hydrocarbon fractions boiling within the motor fuel range to convert said hydrocarbon fractions into motor fuels of substantially improved anti-knock quality. Specifically this invention pertains to an improved hydroforming process for upgrading hydrocarbon fractions boiling within the motorfuel'or naphtha range to increase the aromatic'ity and the anti-knock characteristics of the product.

Numerous processes have been proposed for the conversion or reforming of hydrocarbon fractions boiling Within the motor fuel or naphtha range to increase the aromaticity and improve the anti-knock characteristics of said hydrocarbon fractions. Reforming processes employing catalysts, especially hydroforming and aromatizing are widely used in the petroleum industry to upgrade or improve the anti-knock characteristics of motor fuels. By hydroforming is ordinarily meant an operation conducted at elevated temperatures and pressures in the presence of a solid catalyst and added hydrogen whereby the hydrocarbon fraction treated is increased in aromaticity and in which operation there is no net consumption of hydrogen. The term aromatizing when used broadly refers to conversion reactions which increase the aromaticity of the hydrocarbon fractions. As generally used in the industry, the term aromatizing refers to an operation in whicha hydrocarbon fraction is treated at elevated temperatures in the presence of solid catalysts and in the presence or absence of added hydrogen, usually at pressures lower than those used in hydroforming, for the purpose of increasing the a-romaticity of the hydrocarbon fraction treated.

Catalytic reforming operations are usually carried out at temperatures of around 750-1150" F. in the pressure range of -3000 lbs. per sq. inch and in the presence of such catalysts as molybdenum oxide, chromium oxide, tungsten oxide or, in general, oxides or sulfides of metals of groups IV, V, VI, VII and VIII of the periodic system alone or generally supported on a base or spacing agent. Commonly used spacing agents or supports are alumina gel, precipitated alumina or zinc aluminate spinel. A good catalyst for reforming or hydroforming is one containing about 10% molybdenum oxide on an aluminum oxide base prepared by heat treating a hydrated aluminum oxide. A more heat stable base than-saida-lumina may be prepared by 'com= 2 bin'ing aluminum oxide with zinc oxide, preferably in molecular proportions thereby forming a zinc aluminate spinel.

Hydroforming and aromatizing because of their superior yield-octane relationship and because hydroformed or aromatized gasolines tend to give less engine deposits than thermally reformed naphthas, are the most promising methods for the upgrading of naphthas at the present time. Both processes have been the subject of intensive investigation in an effort to find new catalysts or new conditions for carrying out the conversion to increase yield and/or improve anti-knock characteristics of the product.

It is the object of this invention to providean improved process for catalytically reforming hydrocarbon fractions boiling within the motor fuel boiling range to form motor fuels of higher antiknock ratings in high yields.

It is also the object of this invention "toprovide an improved process for catalytically reforming naphtha fractions to form motor fuels of higher anti-knock ratings in high yields Without any significant eif'ect on either carbon formation or volatility of the motor fuel roduct.

These and other objects will appear more clearly from the detailed specification and claims which follow.

It has now been found that the catalytic reforming of hydrocarbon fractions boiling within the motor fuel boiling range can be carried out more effectively if small amounts of organic acids are added to the naphtha feed to the reforming reactor. Inclusion of small amounts of organic acids in the feed to the reforming reactor produces an improved process in view of the increased yields and the superior product distribution of the reformate.

Typical organic acids which may be used in accordance with the present invention include formic, acetic, propionic, etc, aromatic acids such as benzoic, toiuic, salicylic, phthalic, henylacetic, cinnamic, naphthalic, etc..;. naphthenic acids such as cyclohexane dicarboxylic; as well as acids such as oxalic, succim'c and the like: The amount of organic acid used can be varied over a comparatively wide range, for example from 0.05 to about 0185 Wt. percent based on feed. Preferably from 0.1 to 0.5 wt. percent (on feed) of acid is added to the feed.

The addition of organic acids to the feed can be used to advantage in connection with conventional reforming operations such as hydroforming or aromatization reactions conducted at 0-1 500lbs1pe1 sq. in.-gauge over reformingcatalysts such as molybdenum oxide, chromium oxide, tungsten oxide or, in general, oxides or sulfides of metals of groups IV, V, VI, VII and VIII of the periodic system alone or generally supported on a base or spacing agent. Commonly used spacing agents or catalyst supports are alumina gel, precipitated alumina or zinc aluminate spinel. A good catalyst for reforming or hydroforming is one containing about 10% molybdenum oxide on an aluminum oxide base prepared by heat treating hydrated aluminum oxide. This invention can also be used to advantage in hydroforming over platinum containing catalysts or catalysts having as an active constituent one or more active metals such as iron, nickel, manganese, molybdenum, palladium, vanadium, etc. andalso in hydroforming over fluoride activated catalysts as disclosed in U. S. Serial No. 159,164, filed May 1, 1950, by K. K. Kearby and I. Kirshenbaum.

, The addition of organic acids to the feed can be used in combination with two or more stages and in the presence of 0.1 wt. percent of acetic acid. The catalyst is commercially available under the trade name of Oronite gel hydroforming catalyst and is believed to be prepared in accordance with the disclosures in U. S. Patent 2,432,286. The naphtha had the following inspections:

Initial boiling point, "F 236 Final boiling point, F 396 R. I. n 1.4253 A. P. I. gravity 53.6 Octane number (C. F. R. Research) 40.9

The hydroforming was carried out in the presence of certain amounts of acetic acid at 215 lbs. per sq. inch gauge and at 900-950 with a 2/1 mol ratio of hydrogen to hydrocarbon. Comparative runs were also carried out under the same reaction conditions to the same octane number product but adding no acetic acid. The results obtained are summarized in Table I below:

Wt. Percent Acetic Acid (on feed) Reaction Temperature, F Research Octane Number Gasoline, 04+:

Volume Percent R.V.P., p. s. i

Gas, wt percent..-

Table I EFFECT OF AOETIC ACID ON HYDBOFORMING HEAVY NAPHTHA 1 None 0. 1 None 0. 1 None 0. 1 None 0. 1 None Carbon, wt percent of operation at different pressures or in multistage operations at progressively higher temperatures or with a so-called inverse temperature gradient and in two-stage hydroforming with fluoride activated catalysts as described in U. S. Serial No. 159,309, filed May 1, 1950, by I. Kirshenbaum.

The addition of organic acids to the feed can also be applied to a system in which extraneous saturated or unsaturated gases are added. The organic acids may be added to the reactor system as a separate stream, directly with the feed, with recycle gas, or with extraneous gas.

The pressure and temperature of a two-stage ,process can be the same, higher or lower in the second stage as compared to the first stage. Part of the product from the first stage may be segregated prior topassage of the reaction products through the second stage or tail reactors. The organic acids may be added at one stage or to both stages as desired.

The reforming operation may be carried out with the catalyst arranged in a fixed or moving bed reactors or, it may be carried out according to the so-called fluidized solids technique. In the latter type of operation the catalyst particles are, for the most part, between about and 100 microns in size and the vaporous reactant materials are contacted with catalyst particles main-, tained as a dense, fluidized bed by passing the vapors through the reactor at an apparent velocity of about 1 to about 3 it. per second.

The following example illustrates the advantages that can be gained by the addition of organic acids to the feed to a hydroforming operation.

EXAMPLE 1 .A standard heavy virgin naphtha was subjected to hydroforming in contact with a comecipitated alumina-moylbdena catalyst having the nominal composition of about 91 parts by weight of A1203 and 9 parts by weight of M00:

ill)

It is noted in Table I that the addition of the organic acid increased the C4+ gasoline yield, decreased the dry gas yield and had no significant efiect on either the Reid vapor pressure or the carbon yield.

EXAMPLE 2 The standard naphtha was subjected to hydroforming with the alumina-molybdena catalyst at 900 F. and 215 p. s. i. g. to a Research octane number level of clear. On addition of 0.5 wt. percent acetic acid to the feed a gasoline yield of 94.5 vol. percent on feed was obtained, having a Reid vapor pressure of 5.3 pounds per square inch. In the absence of the added acid the yield was only 93 vol. percent and the Reid vapor pressure was 7.1 pounds per square inch. On a 10 pound Reid vapor pressure basis adding extraneous butanes the gasoline yields were 102 vol. percent for acid addition and 98 vol. percent for conventional operation with no added acid, an advantage of 4 vol. percent for the operation with acid addition.

EXAMPLE 3 The same heavy virgin naphtha was hydroformed with the same catalyst and under the same conditions as in Example I but in the presence of 0.2 wt. percent (on feed) of naphthenic acid instead of acetic acid. The results obtained are summarized in Table 11 below at an 84 Research octane number level.

Table II EFFECT OF NAPH'I HENIG ACID ON HYDROFORMING OF HEAVY NAPHTHA The runs summarized in the foregoing table show that the addition of organic acids such as' acetic or naphthenic acids to heavy virgin naphtha and subjecting the same to hydroforming increases the C 1+ yield by about 2 or more liquid volume percent, decreases dry gas formation by about 1% or more and has no significant effect on either carbon formation or Reid vapor pressure.

The foregoing description contains a limited number of embodiments of the present invention. It will be understood that numerous variations are possible without departing from the scope of the following claims.

What is claimed is:

1. A method of hydroforming hydrocarbon fractions boiling within the motor fuel boiling range which comprises contacting the same with a hydroforming catalyst under hydroforming conversion conditions and in the presence of from 0.05 to about 0.85 wt. percent based on feed of carboxylic acids.

2. A method of hydroforming hydrocarbon fractions boiling within the motor fuel boiling range which comprises contacting the same with a hydroforming catalyst under hydroforming conversion conditions and in the presence of from 0.05 to about 0.85 wt. percent based on feed of acetic acid.

3. A method of hydroforming hydrocarbon fractions boiling within the motor fuel boiling range which comprises contacting the same with a hydroforming catalyst under hydroforming conversion conditions and in the presence of from 0.05 to about 0.85 wt. percent based on feed of naphthenic acid.

4. A method of hydroforming hydrocarbon fractions boiling within the motor fuel range which comprises contacting the same in admixture with a hydrogen-containing gas with a catalyst comprising molybdenum oxide on a spacing agent at temperatures between 800 and 1050 F. and pressures of from 0-1500 lbs. per sq. inch and in the presence of from 0.05 to about 0.85 wt. percent based on feed of carboxylic acids.

5. A method of hydroforming hydrocarbon fractions boiling within the motor fuel range which comprises contacting the same in admixture with a hydrogen-containing gas with a catalyst comprising molybdenum oxide on a spacing agent at temperatures between 800 and 1050 F. and pressures of from 0-1500 lbs. per sq. inch and in the presence of from 0.05 to about 0.85 wt. percent based on feed of acetic acid.

6. A method of hydroforming hydrocarbon fractions boiling within the motor fuel range which comprises contacting the same in admixture with a hydrogen-containing gas with a catalyst comprising molybdenum oxide on a spacing agent at temperatures between 800 and 1050 F. and pressures of from 0-1500 lbs. per sq. inch and in the presence of from 0.05 to about 0.85 wt. percent based on feed of naphthenic acid.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,113,162 Pier Apr. 5, 1938 2,320,147 Layng et a1 May 25, 1943 2,324,708 Liedholm July 20, 1943 2,418,028 Haensel Mar. 25, 1947 FOREIGN PATENTS Number Country Date 416,976 Great Britain Sept. 19, 1934 428,749 Great Britain May 17, 1935 

1. A METHOD OF HYDROFORMING HYDROCARBON FRACTIONS BOILING WITHIN THE MOTOR FUEL BOILING RANGE WHICH COMPRISES CONTACTING THE SAME WITH A HYDROFORMING CATALYST UNDER HYDROFORMING CONVERSION CONDITIONS AND IN THE PRESENCE OF FROM 0.05 TO ABOUT 0.85 WT. PERCENT BASED ON FEED OF CARBOXYLIC ACIDS. 